Increase in the use of stents, leads, and ablation techniques in branch vessels has provided an increased demand on the placement techniques for these devices. For some procedures, it is necessary to initially position a guidewire into a desired part of the lumen of a desired vessel or duct, such as a blood vessel. After the guidewire is positioned within the desired location, a catheter or other tubular device may be positioned over the guidewire and used to convey other medical instruments into the desired blood vessel or duct.
Alternatively, a guiding catheter is used to negotiate the vasculature of a patient. One example of a guiding catheter is described in U.S. Pat. No. 4,898,577 to Badger et al. The Badger guiding catheter includes a single elongate shaft that has a deflectable distal portion controllable by a pull wire. For bi-directional catheters, multiple pull wires are used to pull on the distal end and cause it to defect in more than one direction. One example of such a catheter is shown in U.S. Pat. No. 6,171,277. While bi-directional catheters are helpful, for example, in traversing a complex vasculature, conventional catheters are bulky and have a relatively large outer diameter given the use of multiple pull wires, or the size of the pull wires.
Accordingly, what is needed is a deflectable catheter that overcomes the shortcomings of previous bi-directional catheters. What is further needed is a catheter that allows for more accurate positioning of the distal end of the deflectable catheter, in a less traumatic way.